High frequency klystron tube construction



June 3, 1958 G. c. DALMA'N HIGH FREQUENCY KLYSTRON TUBE CONSTRUCTION .Filed Jan. so, 1953 2 Sheets-She d 1 INVENTOR lsu CD41. MAN BY W .7 A TTORNEY June 3, 1958 G. c. DALMAN 2,837,635

HIGH FREQUENCY KLYSTRON TUBE CONSTRUCTION Filed Jan. so, 1953 2 Sheets-Sheet 2 INVENTOR Gasu C.,DALM/IN ATTORNEY United States Patent ass /gees HIGH FREQUENCY KLYSTRON TUBE CONSTRUCTIQN Gisli C. Dalman, Huntington, N. Y., assignor to Sperry Rand Corporation, a corporation of Delaware Application January 35), 1953, Serial No. 334,365 19 Claims; (Cl. 315-522) The present invention relates to a readily manufacturable, rugged, high frequency klystrontube construction containing very accurately aligned electrodes therein.

Prior art klystrons are comprised of many different mechanicalconstructions which are generally not extremely rugged nor suited to be manufactured with ease of assembly and alignment of the parts thereof. This is especially true with respect to minutely dimensioned klystrons designed for operation at frequencies of the order of eight kilo-megacycles and above. Accurate and rigid coaxial alignment of the cathode and the focussing, grid, and target electrodes in klystrons is necessary in order to obtain optimum efliciency and power output therefrom.

It is an object of the present invention to provide a high frequency beam tube structure of rigid construction whose parts may be readily assembled and accurately spaced in rigid coaxial alignment.

It is a further object of the present invention to provide a high frequency klystron tube construction which is suitable for large scale production,.and which contains electrodes which are easily and very accurately aligned during assembly of the tube.

Another object of this invention is to provide a klystron tube construction containing electrodes which will remain in rigid alignment regardless of shock and vibration of the tube, and wherein the klystron contains a rugged target electrode subassembly.

Otherobjects and advantages of this invention will become apparent from the following specification taken in connection with the accompanying drawings.

The foregoing objects are attained by providing a tubular aligning element as part of the klystron construction. This aligning element may be drawn from a flat piece of metal into a unitary ing a figure of revolution of predetermined configuration. A portion of the interior of said element comprises the cylindrical Wall of a klystron resonator, the aligning element being fixedly situated within an evacuated tubular envelope. A target electrode subassembly and the elements of an electron gun are coaxially located by the. aforementioned aligning element. A, discharge, tube header with connecting leads therethrough is employed for flexible support of a focussing electrode-cathode subassembly by resilient spring means therebetween. After the connecting leads are afiixed to suitable points in the focussing electrode-cathode subassembly for supply of operating voltages thereto, the subassembly is'inserted into the aligning-element in coaxial relationship therewith. The header is sealed to the tubular envelope with the spring meansurging the focussing electrode-cathode subassembly in compression against suitable stop means along the aligning element, for spacing the assembly a predetermined distancefrom thetubes. anode, also coaxiallysupportedby the, aligning; element. T hedetails of the foregoing construction will become. more apparent from the; detailed description infra.

tubular construction forrn- The. target electrode subassembly includes a target electrode structure comprising a metallic cup-shaped member and a metallic stem extending from the back thereof. The stem passes through an annular dielectric body, one end of the stern protruding from the top of said body. The back of the cup-shaped member abuts the bottom of said body. Means are provided to hold the stem in tension, and to maintain the dielectric body in compression between the back of the cup-shaped member-and said means. The dielectric body is rigidly supported in a metallic tubular member by compression means to provide a rugged reflector electrode subassembly which is readily alignable with the rest of the klystron structure. Other detailsand advantages of the aforementioned subassembly will become more apparent from the description infra.

Fig. l is a sectional view or" a reflux klystron embodying the present invention;

Fig. 2 is an exploded view of an upper portion of the klystron shown in Fig. l, and illustrates how the parts.

of the reflector electrode subassembly are fitted together;

Fig. 3 is a view of the tubular aligning element of the klystron shown in Fig. 1, and illustrates how the target electrode and klystron drift tube subassemblies are assembled in relation to said aligning element and supported thereby;

Fig. 4 is a view of a further stage of assembly of the klystron shown in Fig. l, and illustrates how the tubular aligning element and structure supported thereby is assembled with the klystron tubular envelope and output wave guide assembly. Fig. 4 also illustrates how the electron gun subassembly is located by the aforementioned tubular aligning element to be coaxially positioned with respect to the grid and target electrodes of the klystron; and

Fig. 5 is a sectional view of the klystron along the line 5-5 of Fig. 1.

Referring to Fig. 1, a reflex klystron construction is shown, comprising an electron gun subassembly 11, a smoother or anode grid 12, an electron drift space 13, a reentrant cavity resonator 14, entrance and exit resonator grids 15 and 16 respectively, and a target electrode comprising a reflector electrode structure 17.

The aforedescribed klystron elements are coaxially supported in a cylindrical metal envelope 19 of the type used for standard metal receiving tubes. Envelope i9 is provided with an end piece 20 having a threaded aperture therein for support of a tuning mechanism which will be described more fully below. The cylindrical Wall of envelope 19 contains a punched, rectangular-shaped opening therein which is aligned with the open end of a transmission linecomprising a rectangular output wave guide 23. Wave guide 21 includes a dielectric window 18 for maintaining a vacuum within the klystron tube.

An approximately semiannular metallic body 22, having an outer diameter which is conformal to the inner diameter of envelope 1% (Figs. 1, 4 and 5), is inserted within envelope 19. Body 22 and envelope 19 are brazed together with an alloy of relatively high melting point. Body 22 has two coplanar ends 23 and 24- which include anopening therebetween as is shown in Fig. 5. The ends 23 and 24 are aligned with the aforementioned rectangular opening in envelope 19 and provide a part of a terminating end wall for wave guide 21.

The cylindricalwall of resonator l4 fits snugly within the body 22 and is coaxial therewith. A portion of the cylindrical resonator wall (shown in Fig. 5) protrudes a slight distance into the end of wave guide 21 past the plane containing the coplanar ends 23 and 24 of body 22. This portion contains a rectangular or other suitably shaped coupling aperturenor iris 26 opposite the rectangular opening in envelope 19 to provide a coupling means for electromagnetically coupling resonator 14 to wave guide 21.

The metallic body 22, besides serving as a supporting and aligning element of the tube structure, provides an eificient heat conducting path for cooling the klystron. Heat developed in the interior of the klystron will be readily conveyed by body 22 to the tubular envelope 19, which may be air-cooled if desired.

Body 22 also comprises a means for supporting a reflector lead housing assembly 25, shown in Figs. 1 and 4, as will be explained more fully below.

Plate elements 27 and 28, each having a central aperture therein, are brazed to envelope 19. These plate elements comprise the upper and lower walls, respectively, of the extension of wave guide 21 between resonator 14 and the cylindrical wall of envelope 19.

The klystron shown in Fig. 1 operates in a conventional manner requiring no description herein. Tuning of the klystron resonator 14 is effected by a differential screw tuning mechanism which is utilized to change the spacing between grids 15 and 16 of resonator 14, and thus, the resonant frequency of resonator 14.

The aforementioned tuning mechanism comprises a tuner screw 29 and a threaded element 38. Screw 29 is provided with an external thread having a predetermined pitch and direction of winding for engagement with a threaded aperture in the end piece 20 of tubular envelope 19, as is shown in Fig. 1. Screw 29 is also provided with a socket portion having an internal thread wound in the same direction but having a slightly smaller pitch than the aforementioned external thread. The threaded socket portion of screw 29 is adapted to engage the threaded element 30.

And end section 31 of threaded element 30 is welded to a tubular member 32, which in turn, is brazed to a flexible resonator diaphragm 33. Element 30 is also brazed to a flexible vacuum diaphragm 51, which in turn, is brazed to the inner wall of envelope 19. Therefore, threaded element 30 is held against any rotational movement. However, element 30 can be moved in an axial direction because of the flexibility of diaphragms 33 and 51.

Screw 29 is externally threaded, for instance, so that clockwise rotation thereof will produce a downward axial movement thereof. Since element 39 is not rotatable, is

threaded in the same direction as the external thread of screw 29 but with a smaller pitch, it will move in an upward axial direction at a rate which is a fraction of the rate of downward movement of screw 29. counterclockwise rotation of screw 29 causes downward axial movement of element 30 at the same reduced rate.

A stop member 69 is affixed to element 30 to limit the axial movement thereof. Downward movement of element 38 is limited by abutment of member 69 against a plate element 78 attached to diaphragm 51. Upward movement is limited by the abutment of the adjacent ends of screw 29 and stop member 69. Spring element 71 is provided, as shown, to eliminate backlash in the tuning mechanism.

Diaphragm 33 supports the resonator exit grid 16. Since diaphragm 33 is attached to threaded element 30 by member 32, movement of element 39 causes the diaphragm 33 and grid 16 to move relative to resonator entrance grid 15. Therefore the resonant frequency of resonator 14 may be readily varied by adjustment of screw 29.

The novelty of the present disclosure relates to the particular mechanical features of the klystron whereby it may be readily fabricated in small sizes, is of extremely rugged construction, and contains very accurately aligned electrodes therein. The rugged construction and relative ease of assembly and alignment of the parts of the klystron will become apparent from the following description of Figs. l-4, where corresponding reference numer- Cir original diameter.

4 als for various parts of the klystron construction have been used.

Referring to Fig. 2, a centrally apertured resonator diaphragm 33 is shown, which is brazed with an alloy of relatively high melting point to the bottom end of metallic tubular housing member 32. A jig is employed before and during the brazing operation to insure that diaphragm 33 is assembled in coaxial relationship with tubular member 32. The curved wire mesh resonator exit grid 16 is then welded across the aperture in diaphragm 33.

A centrally apertured annular dielectric body 34, having an annular depression or reduced diameter section 35, and the reflector electrode structure 17, which comprises a metallic dish or cup-shaped member 36 joined to a metallic stem 37, are then fitted together. The diameter of the larger sections of body 34 is conformal to the inner diameter of tubular member 32, in which body 34 is to be supported.

The dielectric body 34 is seated upon the back of cupshaped member 36 so that the stem 37 extends through and protrudes from the aperture in body 34, as is shown in Fig. 1. A ring of metal 38 is then placed over the protruding end of stem 37 and rests on the top of body 34. Soldering material having a relatively high melting point is utilized with metal ring 38 so that the ring may be affixed to stem 37.

The assembly comprising elements 17, 34, 38, and the soldering material, is then heated to a temperature corresponding to the melting point of the aforementioned soldering material. The heat causes the stem 37 to expand longitudinally and the soldering material to melt. During the heating process the ring 38 and the back of cup-shaped member 36 are held in temporary compressive abutment against the top and bottom of body 34, respectively. This permits the stem 37 to protrude further beyond the end of the relatively non-expandable dielectric body 34 when stem 37 thermally expands from the heating.

Heat is applied to the structure 17, 34, 38 until the aforementioned soldering material wets the adjacent surfaces of ring 38 and stem 37. Then the structure is cooled so that the ring 38 and stem 37 are affixed together by the solder. Cooling of the structure from the solidification temperature of the solder to room tempera ture causes a permanent compressive force to be maintained between ring 38 and the back of member 36 against the dielectric body 34. This occurs because the ring 38 has become afiixed by the solder to stem 37, and stem 37 has a tendency to contract to its original (room temperature) length during cooling. This pulls ring 38 in tight abutment with the top of body 34 and the back of member 36 in tight abutment against the bottom of body 34. Therefore the stem 37 is held in tension, and the dielectric body 34 is maintained in permanent compression between the back of member 36 and ring 38.

A reflector connecting lead 39 is then welded to the cup member 36 of the reflector electrode structure 17. After this step, a ring of solder 40 (having a melting point lower than any solder or brazing material heretofore utilized in the reflector subassembly shown in Fig. 2) is placed in the reduced diameter section of dielectric body 34. Then the structure is inserted a predetermined distance into the metallic tubular member 32, body 34 fitting snugly within member 32.

The aforementioned reflector electrode subassembly is then heated to the melting point of ring 40. When the structure is heated the member 32 expands to a slightly larger diameter, and some of the solder of ring flows a short distance into the resulting space between the inner cylindrical surface of member 32 and the two larger cylindrical surfaces of body 34. Cooling to room temperature causes the member 32 to contract to its aforementioned contraction is opposed at the places where the solder exists between the dielectric body 34 and the inner wall of member 32. Therefore the reflector elec- Upon hardening of the solder the it trode structure 17is caused to be maintained in arigid and permanent longitudinal position with respect to tubular housing member 32, as shown in Fig. 1.

The lower end section 31 of the threaded element 39 in Fig. 2 is then welded. to the inner wall of tubular member 32, section 31 occupying the space along the wall of member 32 above the dielectric body 36 as shown in Fig. 1.

The reflector electrode subassembly, comprising the elements shown in Fig. 2, is then inserted into the larger diameter end of a metallic tubular aligning element 41, and upward into element 41 as shown in Fig. 3. Element 41 has a first section-42 of large diameter, another section 43 of smaller diameter, and an intermediate tapered section 44 therebetween. Tubular element 41 comprises a unitary structure which may be drawn from a flat piece of metal to form a figure of revolution. Sections 42 and 43 of element 41 are therefore coaxially aligned.

A jig is employed to maintain the subassembly comprising the elements shown in Fig. 2 coaxial with the tubular aligning element 41 during the assembly stage shown in Fig. 3. After insertion of the aforementioned subassembly to the smaller end of aligning element 41, the diaphragm 33 is welded to an inwardly flanged portion of element it in a final position shown in Figs. 1 and 4.

Next the drift tube-smoother grid subassembly is formed as is shown at the bottom of Fig. 3. The klystron drift tube includes the inner wall of a tapered tubular member 46 and the aperture in a circular washer 48 as is shown more clearly in Fig. l. A flanged end 47 of member 4-6 is welded to washer 48 as is shown in Figs. 1

and 3. A jig is employed during this step to insure the alignment of member 46 and Washer 48. Washer 48 has an outer diameter which is conformal to the inner diameter of section 43 of tubular aligning element 41. A curved wire-mesh resonator entrance grid is welded or brazed to the smaller diameter end of tapered tubular member 46. I

A curved wire-mesh smoother grid 12 is Welded to another circular metallic washer 4h. A jig is preferably employed during this step to insure that the axes of. washer 49 and grid 12 are made coincident. Washer 49 has. a relatively small thickness compared to washer 4S, and a diameter which is equal to that of washer 48.

The washers i8 and 49 are made coaxial and then assembled by welding. The washers lii and 49 and structure supported thereby are then inserted by means of a jig into the tubular aligning element 41. After insertion to a predetermined distance the washer 43 is tack welded to. the aligning element 41 in the position shown in Figs. 1 and 4.

In Fig. 4 the outputwave guide 21 is shown assembled with the tubular envelope 1& of the xlystron, the approximately semiannular body 22 being brazed with an alloy of relatively high melting point in the proper position in envelope l9. The tubular aligning element 41 and parts (shownin Fig. 3) supported thereby are insorted into the tubular envelope 19. The outer diameter of the section 4 f tubular element 41 is conformal to the inner diameter of the approximately semiannular body 22 so that section 43 may be inserted into and fitted snugly within body 22. I

After insertion of the tubular aligning element 43 and parts supported thereby to the position in envelope 19 shown in Fig. l, the reflector lead 39 is welded to an insulated metallic sleeve 56 extending from the reflector lead housing 25.

Nexta brazing alloy (having a lower melting point than any heretofore described) is employed to braze element 41 to body 22, and to permanently braze washers 48 and 49 to the inner Wall of element 41.

At the same. time diaphragm 51, which is utilized to form a vacuum 59 and are spot welded to member 62.

seal, canbe brazed to the inner wall of envelope 19 and to the upper portion of end section 31 of the threaded element 30 of the reflector electrode subassembly. This is also shown in Fig. 1.

The klystron electron gun subassembly 11, shown in detail in Fig. 1, comprises a cathode button 52 and a focussing electrode 53.

Electrode 53 is a hollow cylinder which includes an inwardly extending flange 54 at one end thereof. Flange 54 is welded to an inwardly extending flange portion 55 of a metallic tubular supporting member 56. A jig is employed to insure their coaxial alignment during assembly. The lower end of member 56 is outwardly flanged as shown.

The cathode button 52 is seated and welded at one end of a cylindrical metallic foil supporting member 57, which in turn, is welded to a dish-shaped member 5 in the position shown by Fig. 1.

The axes of the fccussing electrode supporting member 56 and the cathode button supporting structure 57, 58 are then made coaxial by means of a jig, and member 58 is spot welded to the outwardly extending flange at the bottom of member 56. Members 56 and 58 are then supported on dielectric insulating disk member 59, the diameter of member 59 being conformal to the inner diameter of section 42 of the tubular aligning element 41. A jig is preferably employed during the aforementioned supporting step to insure alignment ofrmembers 56 and 53 with the axis of disk member 59. During this step three rivets, only one of which is shown at 61, are employed to rivet the outwardly flanged end of member 56 to the dielectric disk member 59.

Dielectric disk member 59 is then fastened by U- shaped wire elements 66' to a tubular member 62. The ends of elements 60 are punched through the member Member 62 includes an outwardly extending flange 63 having an outer diameter slightly smaller than the diameter of the dielectric disk member 59. A header 64 (shown in Fig. 4) is fastened to member 62by means of spring elements 66. Three such spring elements are welded to member 62 and header 64 to support the aforedescribed electron gun subassembly 11 on the header.

The electron gun or focussing electrode-cathode subassembly lll is then inserted into the tubular aligning element 41, as is shown in Fig. 4. Three or more tabs 67 are provided on the cylindrical wall of tubular element 41 to provide stops in a common plane perpendicular to the axis of the klystron tube. These tabs 67 along with the interior wall of section 42 of aligning element 41, determine the proper location and axial relationship of the electron gun subassembly with the rest of the klyst-ron. The springs 66 aid in the coaxial alignment of the electron gun structure by insuring that dielectric disk member 59 is maintained in rigid, compressive abutment against tabs 67 when the header 64 is properly mounted on the rest of the klystron structure. Since the diameter of disk member 59 is conformal to the inner diameter of section 42 of tubular aligning element 41, coaxial alignment of the axes of the electron gun subassembly 11 and the grid and target electrodes of the klystron is insured.

Suitable electrode connecting means are supported on the header 64, and are connected to the required elements of the electron gun subassembly 11 in any suitable manner. Connection to the reflector structure 17 is effected by reflector connecting element 68. When the header 64 of the klystron is sealed to member 19, connecting element 68 fits snugly within the metallic tubular reflector electrode connecting sleeve 5! After insertion of the electron gun assembly into tubular element 41 to the proper position, a flange 72 at the bottom of the header 64 (Fig. 4) is brazed to a flange 73 at the bottom oftubular envelope 19. This provides a vacuum seal for the klystron and substantially completes the assembly.

As is apparent from the foregoing description thereof, the present klystron tube construction can be readily fabricated by assembly-line methods. The reflector electrode subassembly, the electron gun subassembly, the drift tubesmoother grid subassembly, and the output wave guide and tubular envelope subassernbly are each distinct and readily fabricated. The subassemblies can be constructed in extremely small sizes if required. Each subassembly is of rugged construction and so designed that it may be rigidly and accurately aligned with the others by a coaxial supporting tubular aligning element as described above. Since the aligning element is drawn from a flat piece of metal, it can be inexpensively and accurately produced in accordance with a predetermined design.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accornpanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A high frequency discharge tube, comprising means including an electron permeable anode and a focussing electrode-cathode subassembly for producing and directing an electron beam through said anode along a predetermined axis, a tubular evacuated envelope portion surrounding said beam producing means, a conductive tubular aligning element, said anode being connected to and rigidly supported in coaxial relationship with said aligning element, means rigidly supporting said aligning ele ment and anode within said envelope portion, a dielectric member coaxially supported by a tubular wall portion of said aligning element, Stop means along said aligning element for spacing said dielectric member at a predetermined distance from said anode, said dielectric member supporting said focussing electrode-cathode subnssembly within said aligning element in electrically insulated, co-

axial relationship relative to said aligning element and anode, means precluding axial displacement of said subassembly from said dielectric member in the direction of said anode, electron discharge tube header means having connecting leads therethrough connected to predetermined points in said focussing electrode-cathode sub assembly for supply of operating voltages thereto, resilient spring means between said subassembly and header for flexible axial support of said subassembly by said header, and means rigidly affixing said header in vacuum sealed relationship to said tubular envelope portion for compression of said spring means and maintenance of said dielectric member in abutment against said stop means to thereby firmly locate said focussing electrode-cathode subassembly at a predetermined axial position relation to said anode.

2. A high frequency discharge tube as set forth in claim 1, further including high frequency utilization means rigily positioned within said envelope in coaxial relationship with said aligning element for exchange of energy with said electron beam after passage through said anode. 7

3. A high frequency discharge tube as set forth in claim 2, wherein said discharge tube comprises a klystron, said utilization means comprising an electromagnetic resonator having electron permeable resonator gap means aligned with said beam, said resonator having a tubular side wall formed by a part of said tubular aligning element. I

4. A high frequency klystron structure comprising an evacuated envelope, an electron gun subassembly, a target electrode subassembly, an electromagnetic resonator in cluding electron permeable means for passage of electron beam therethrough, said electron permeable means being intermediate of said electron gun and target electrode subass-emblies, tubular aligning means locating said subassemblies in coaxial alignment with each other and with the electron permeable means of said resonator, a portion of the inner wall of said tubular aligning means comprising a conducting wall of said electromagnetic resonator, and means within said evacuated envelope rigidly maintaining said tubular aligning means fixedly situated within said evacuated envelope, said tubular aligning means comprising a first section of predetermined diameter, a second section of predetermined diameter which is different from said first section, and an intermediate connecting section therebetween, said electron gun and target electrode subassemblies being coaxially aligned by the first and second sections of said tubular aligning means respectively.

5. A high frequency klystron structure as defined in claim 4, wherein said electromagnetic resonator includes upper and lower walls, said upper wall comprising an electron permeable diaphragm supported at the end of the second section of said tubular aligning means most remote from said electron gun subassembly, said lower resonator Wall comprising a metallic washer element fitting snugly Within and supported by said aligning means at an intermediate position within said aligning means.

6. high frequency klystron structure as defined in claim 5, wherein said lower resonator wall supports a klystron drift tube and electron permeable grid subassembly in coaxial relation with said tubular aligning means, said electron gun subassembly being coaxially located by said aligning means at a predetermined position below said drift tube and electron permeable grid subassembly.

7. A high frequency klystron tube structure, comprising an evacuated envelope portion, a unitary, metallic tubular aligning element Within said envelope portion and affixed thereto, an electron gun including a cathode subassembly and an electron permeable anode for producing and directing an electron beam along a predetermined axis, said cathode subassembly being coaxially located within said aligning element by dielectric support means engaging an inner tubular wall portion of said element, stop means along said aligning element for abutment by said dielectric member for spacing said cathode subassembly from said anode, a header afiixed to one end of said envelope portion, resilient spring means between said header and cathode subassembly for compressing said subassembly and dielectric support means in place at a predetermined location along said aligning element, an electron permeable anode spaced a first distance from said cathode and supported within said aligning element in coaxial relationship therewith, means including said aligning element for supporting an electron permeable resonator, said resonator including a velocity modulation gap region spaced a further distance from said cathode than said anode and coaxially located therewith, and a further subassembly including a target electrode, said further subassembly being supported by said aligning element in coaxial relationship with said cathode, said target electrode being rigidly supported in said further subassembly at a further distance from said cathode than said gap region.

8. A velocity-modulation electron discharge device, comprising a metallic tubular aligning element, means engaging a tubular wall of said aligning element for supporting an electron gun subassembly in coaxial alignment with the axis of said element, means defining an electron permeable electromagnetic resonator, said resonator defining means including a portion of the inner wall of said tubular aligning element, a target electrode structure, a tubular housing member, means supporting said target electrode structure in concentric relationship within said tubular housing member, and further means coaxially supporting said housing member on said aligning element so that said resonator is intermediate of said target electrode structure and said electron gun subassembly, said electron gun subassembly, said electromagnetic resonator, and said target electrode structure being maintained in rigid coaxial alignment.

9. A velocity-modulation electron discharge device as defined in claim 8, wherein said target electrode structure comprises a metallic cup-shaped member with. a metallic stem extending therefrom, said means supporting said target electrode structure in concentric relationship with said housing member comprising a dielectric body rigidly supported within said housing member, said dielectric body having a concentric aperture therein for receiving the stem of said target electrode structure, the stem side of said cup-shaped member abutting said dielectric body,

and means rigidly supporting said stern within said dielectric body, said last-named means maintaining said stem in tension and said body in compression between the back of said cup-shaped member. and said last-named means.

10. A velocity-modulation electron discharge device as defined in claim 8, and further including an evacuated, metallic tubular envelope, said envelope having an opening in a wall thereof for alignment with an electromagnetic transmission line, said tubular aligning element having an aperture in the resonator wall portion thereof, and means rigidly supporting said tubular aligning element within said tubular envelope with said opening in the wall of said envelope adjacent to and in communication with the opening in said resonator wall portion of said aligning element.

11. A rugged klystron tube structure, comprising a metallic tubular envelope having a cylindrical cross section, an opening in the cylindrical wall of said envelope for alignment with an electromagnetic transmission line, an approximately semiannular body of metal coaxially supported within said tubular envelope, said body having coplanar, spaced ends adjacent said opening in said wall of said envelope, the space between said coplanar ends being aligned with said opening, ametallic tubular aligning element having a cylindrical section coaxially supported in said body, said cylindrical section including an aperture which is positioned approximately between the coplanar ends of said body, a target electrode subassembly, an electron gun subassembly, said subassemblies being coaxially located by. said tubular aligning element on opposite sides of said aperture in said element, and means defining an electron permeable electromagnetic resonator within said tubular aligning element between said target electrode subassembly and electron gun subassembly.

12. A high frequency klystron tube structure, comprising a metallic tubular envelope, an opening within a section of said envelope for alignment with an end of a microwave transmission line, a metallic body having a cylindrically-shaped interior portion extending along an axis of said body, said axis being concentric with the axis of said tubular envelope, a portion of the periphery of said body conforming to and fitting snugly within and supported by said tubular envelope, said body including an opening from said interior portion to said periphery,

said opening from said interior portion to said periphery of said body being spaced from said axis and aligned with the opening in said tubular envelope, a metallic tubular aligning element fitting snugly within and coaxially supported by the interior-portion of saidmetallic body, said tubular aligning element having a cylindrical wall section which includes an aperture therein, the aperture in said cylindrical wall section of said aligning element being adjacent to and in communication with the opening from the interior portion to said periphery of said body, electron gun and target electrode subassemblies, said subassemblies being coaxially located by said tubular aligning element on opposite sides of said aperture in the cylindrical wall of said aligning element, and means defining a microwave resonator within a portion of said tubular aligning element between said electron gun and target electrode subassemblies, a portion of the cylindrical wall section of said tubular element which includes said aperture comprising the outer wall of said resonator.

13. A high frequency klystron tube structure, comprising a tubular envelope, a metallic tubular aligning element rigidly supported within said envelope, means for producing and directing an electron beam along a predetermined axiswithin said tubular envelope, said means being, coaxially located by said tubular aligning element within said envelope, electron permeable anode means spaced along said axis from said beam producing and directing means, said anode means being coaxially supported within said tubular aligning element, means definingan electron permeable resonator within said aligning element at a position further along said axis beyond said anode means, a portion of the wall of said aligning element comprising a wall of said resonator, a target electrode structure, ametallic, tubular housing member, means rigidly supporting said target electrode structure in concentric relationship within said housing member, said last-named means comprising a dielectric body, said body being supported within said tubular housing member by compression means, further compression means supporting a portion of said target electrode structure within said dielectric body, and means coaxially supporting said tubular housing member within said tubular envelope, said target electrode structure being coaxially located along the axis of said electron beam at a position beyond said resonator.

14. A high frequency klystron tube structure as defined in claim 13, wherein said target electrode structure comprises a cup-shaped metallic member and a metallic stem extending therefrom, said dielectric body havingpa concentric aperture therethrough for receiving said stem, the back of said cup-shaped member abutting one end of said dielectric body, and ring means supported at the other end of said dielectric body, means aflixing said ring means to said stem, said ring means holding said stem in tension, and maintaining said dielectric body in compresison between the back of said cup-shaped member and said ring means to thereby rigidly support said reflector electrode structure with respect to said. dielectric body.

15. An electrode subassembly for a high frequency discharge-tube, comprising a tubular metallic housing, a target electrode structure comprising a metallic electrode member and. a metallic stem extending therefrom and afiixed thereto, an apertured dielectric body for receiving said stem, the outer periphery of said dielectric body conforming to the inner wall of said tubular housing, peripheral depression means in said body intermediate the ends thereof, means afiixed to said housing and cooperating with said depression means for fixedly locating said body within said housing, a portion of said electrode structure being larger than the aperture of said body and abutting one end of said body, the stern of said electrode structure being conformal with the aperture of said dielectric body and extending therethrough so that a portion of said stem is beyond the other end of said body, and means afiixed to said stem portion during a state of thermal expansion of said stem for maintaining said stem in tension and maintaining said dielectric body in compression between said means and said electrode member.

16. A target electrode subassembly for a klystron tube, comprising a metallic, tubular housing member, an annular dielectric body fitting snugly within said member and coaxial therewith, depression means in the annular periphery of said body, means rigidly supporting said body within said housing member, said means being eflixed to the inner wall of said member and exerting a compressive force against said body at said depression means, a metallic electrode member which is wider than the diameter of said aperture in said dielectric body, a metallic stem afiixed to said metallic electrode member, said stem fitting snugly within the aperture of said body, and means united with said stem and rigidly maintaining said metallic electrode member in compressive relationship with respect to said body.

17. A target electrode subassembly for a high frequency discharge tube, comprising a metallic, tubular housing member, an annular dielectric body fitting snugly I 11 within said member in coaxial relationship therewith, at least one depression in the annular periphery of said body, solder means affixed to said housing member, a

portion of said solder means protruding into said depression, said solder means exerting compressive force against said dielectric body in the vicinity of said depression for rigid axial support of said body within said housng member, a metallic electrode member at one end of said dielectric body, a metallic stem affixed to said electrode member, at least a portion of said stem fitting snugly within at least a portion of said dielectric body in coaxial relationship therewith, and a ring of solder united with said stem during a state of thermal expansion thereof and rigidly maintaining said metallic electrode member in compressive relationship with respect to said dielectric body at said one end thereof.

18. A rugged target electrode subassembly for klystron tubes, comprising a tubular housing member of metal having a longitudinal axis, an annular body of dielectric material within the interior of said housing member, said annular body having an aperture therethrough which extends parallel to said longitudinal axis, a first region of said body fitting snugly within the inner wall of said housing member and a second region of said body being of reduced cross section compared to said first region, solder means united with a portion of the wall of said housing member adjacent the second region of said body and exerting a compressive force against said body at said second region, a target electrode structure having a portion thereof abutting against one end of said body, a metallic stem extending from said portion, said stem fitting snugly within the aperture of said body and extending to a region adjacent a second end of said body opposite to said one end, and means united with a portion of said stem adjacent said second endof said body and maintaining said portion of said electrode structure in compression against said body.

19. A reflex klystron tube structure, comprising an electron gun subassembly for producing an directing an electron beam along a predetermined axis, a metallic tubular aligning element of unitary construction having a longitudinal axis coincident With said predetermined axis, a first section of said element extending parallel to said axis and a second section of said element being flared outwardly from said axis, means supporting said electron gun subassembly with respect to said tubular element adjacent the flared end of said element, said aligning element coaxially locating said electron gun subassembly along said axis, a smoother grid and drift tube subassembly spaced along said axis from said electron gun structure, means coaxially supporting said grid and drift tube subassembly Within said tubular element, a first electron permeable grid supported at the end of said drift tube furthest from said electron gun structure, a metallic diaphragm containing a second electron permeaable grid spaced a short distance along said predetermined axis beyond said first grid, means supporting said diaphragm at the end of said tubular aligning element opposite said flared end to coaxially position said second grid with respect to said predetermined axis, said diaphragm and said means supporting said drift tube forming the upper and lower walls of a cavity resonator respectively, the inner wall of said tubular aligning element between said diaphragm and said means supporting said drift tube comprising a cylindrical wall of said resonator, the periphery of said drift tube comprising a reentrant portion of said resonator, a reflector electrode structure beyond said resonator, means supporting said structure on said diaphragm in coaxial relationship with said predetermined axis, whereby the electron gun subassembly, the smoother grid and drift tube subassembly and said reflector electrode structure are maintained in rigid, coaxial alignment with each other.

References Cited in the file of this patent UNITED STATES IATENTS 2,494,693 Ekstrand et al. Jan. 17, 1950 2,508,346 Laiferty May 16, 1950 2,513,359 Pierce July 4, 1950 2,566,584 Shepherd Sept. 4, 1951 2,614,233 Joerndt Oct. 14, 1952 

